Owned by privately run company BritNed Development Limited, BritNed is the first subsea electricity interconnector to exist between the UK and the Netherlands. Designed to push beyond one European sector, BritNed is a cable that stretches across the North Sea, creating a connection between two countries that rely on a source of energy.
It is 260km in length and has 100% accessibility, with a constant supply flowing back and forth to where it is needed. BritNed was conceived to offer a safe, reliable and extremely efficient source of electricity and with a capacity of 1000 MW BritNed certainly has the power to do just that.
BritNed commercial director René Kerkmeester said: “Via market coupling BritNed provides UK traders for the first time a gateway to the highly liquid European market.
“Earlier experience of coupling across border markets has witnessed an increase of liquidity and volumes and the creation of a stable reference price.
“We expect that the UK market will now benefit from the same experience.”
BritNed connects the Isle of Grain, north Kent, in the UK with the industrial area of Maasvlakte, near Rotterdam in the Netherlands and it’s this union that is truly at the heart of the process. It was devised and put into operation as a joint venture between National Grid Holdings One PLC in Great Britain and TenneT Holding B.V in the Netherlands.
The process aims to strengthen the European energy market by ensuring that there is a reliable supply of electricity flowing between the two countries. By putting BritNed into operation, the aim is to work towards streamlining the electricity market in Europe, so that it can eventually become one international electricity market.
As the supply is for both domestic and industrial consumers, BritNed auctions the cable’s capacity on the open market and the price of the electricity is dependent on costs within both power markets. It is believed that this will eventually even out the escalating costs of electricity, to create a fairer process in the future. It doesn’t buy or sell any of the electricity; instead companies that trade on BritNed will have the ability to bid on the basis of one day ahead, known as implicit auctions, or through set capacities, known as explicit auctions. This can allow the purchase of capacity up to one year in advance.
This forward thinking process will benefit both consumers and the industry as a whole and offers a more secure source through a connection between two separate, yet established markets.
Secretary of State for Energy and Climate Change, Chris Huhne said: “This is good news for our energy security, for UK renewable and for consumers.
“It plugs the UK directly into a wider European electricity market, allowing us to import our peak needs cheaply rather than hold expensive plants in readiness.”
As a company, BritNed Development Limited is funded commercially so that it functions as an independent business that can be regulated and monitored to ensure the highest standards of safety and efficiency. This is something the company prides itself on and by investing in the interconnector BritNed Development Limited has been able to join the wider European electricity market.
Budgeted at around €600m the BritNed cable went live in April 2011 but was first conceived in 1999 when a study into its feasibility was started. This was followed by an offshore seabed survey before the company awarded contracts to its construction partners in 2007.
Work officially commenced on the project in Maasvlakte in September 2009 as part of a three-pronged process that saw the subsea cable manufactured and installed below the North Sea. This was followed by two convertor stations, one at either end of the cables. Electrical equipment needed to complete the process of transferring the current was then installed in the convertor stations.
In order to lay the cable, two HVDC power cables were bundled and buried together approximately a metre below the seabed of the North Sea, at a depth of between 30 – 50 metres. This operation required over 30 special cable-laying vessels and support vessels and was split into seven sections.
The BritNed cable carries a current of electricity with a voltage of ± 450 kV DC and is a combination of two 250 km sea cables and two land cables laid together at 7 km in the Netherlands and 2 km in Great Britain. The BritNed cable weighs 23.000 tonnes and due to the distance of transmitting across both marine and land cables it was designed to carry a direct current. This meant that at either end of the cable, a convertor station was constructed to transform the direct current into alternating current, which is the current that is transmitted in both countries.
The convertor stations, approximately 5 hectares in size, were built at the Isle of Grain and Maasvlakte to either convert alternating current into direct current, or DC back into AC. This required the installation of electrical equipment and components and so at the centre of each station is the valve hall which contains 12-pulse optically triggered thyristor valves, to make the conversions. An AC cable system connects the convertor station with the Isle of Grain’s 400kV substation, whilst the convertor station at Maasvlakte links via an overhead line to the TenneT 380kV substation.
To regulate the AC power system voltage seven convertor transformers were installed at each station, with six working on the operation at each location and one remaining transformer acting as a spare.
BritNed’s Interconnector was installed to the highest standards of civil, electrical and marine engineering and its implementation adhered to its policy of providing safety for its staff, its customers and the environment it operates within.
As mentioned previously, BritNed has been in the pipeline for over a decade and so every care was taken to work with local experts to ensure that the disruptive impact it could have on the area was kept to a minimum. With work complete, testing took place in late 2010, with the first explicit and implicit auctions beginning in March 2011.
BritNed provides greater opportunities for import and export, by opening up access to all players in the market by increasing the diversity of supply.
Executive director of National Grid, Nick Winser said: “Our investment in this interconnector means that we are joining a much wider European electricity market. This ability that we will now have to move power across national borders means we can use the full potential of renewable energy from wind – making it easier to import when wind is not available and export when there is a surplus.”
Secretary of State for Energy and Climate Change, Chris Huhne added: “Renewables win as it means surplus wind power can be easily shared. Consumers win as a single European market puts pressure on prices.”
With plans for an additional 10GW of electricity available under the North Sea by 2020 BritNed Development Limited believe that with BritNed in place, the connection should encourage similar processes in the electricity grid in the coming years.